package com.vmladenov.cook.core;

import java.io.File;
import java.util.HashMap;
import java.util.Stack;

import android.app.Activity;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Environment;
import android.widget.ImageView;

import com.vmladenov.cook.R;
import com.vmladenov.cook.core.html.SmallPreview;

public class ImageLoader
{
	// the simplest in-memory cache implementation. This should be replaced with
	// something like SoftReference or BitmapOptions.inPurgeable(since 1.6)
	private HashMap<SmallPreview, Bitmap> cache = new HashMap<SmallPreview, Bitmap>();

	private File cacheDir;

	private final Context context;
	private final Boolean cacheImages;

	public ImageLoader(Context context)
	{
		this.context = context;
		photoLoaderThread.setPriority(Thread.NORM_PRIORITY - 1);
		cacheDir = getCacheDir();
		AppSettings settings = new AppSettings(context);
		cacheImages = settings.cacheImages();
	}

	private File getCacheDir()
	{
		String state = Environment.getExternalStorageState();
		if (Environment.MEDIA_MOUNTED.equals(state) || Environment.MEDIA_MOUNTED_READ_ONLY.equals(state))
		{
			String directory = context.getExternalFilesDir(null) + "/images/";
			File directoryFile = new File(directory);
			if (!directoryFile.exists()) directoryFile.mkdir();
			return directoryFile;
		}
		return null;
	}

	final int stub_id = R.drawable.icon;

	public void DisplayImage(SmallPreview preview, ImageView imageView)
	{
		if (cache.containsKey(preview))		
		{
			Bitmap bitmap = cache.get(preview);
			if (bitmap != null)
				imageView.setImageBitmap(bitmap);
		}
		else
		{
			queuePhoto(preview, imageView);
			imageView.setImageResource(stub_id);
		}
	}

	private void queuePhoto(SmallPreview preview, ImageView imageView)
	{
		// This ImageView may be used for other images before. So there may be
		// some old tasks in the queue. We need to discard them.
		photosQueue.clean(imageView);
		PhotoToLoad p = new PhotoToLoad(preview, imageView);
		synchronized (photosQueue.photosToLoad)
		{
			photosQueue.photosToLoad.push(p);
			photosQueue.photosToLoad.notifyAll();
		}

		// start thread if it's not started yet
		if (photoLoaderThread.getState() == Thread.State.NEW) photoLoaderThread.start();
	}

	public Bitmap getBitmap(String imageUrl)
	{
		if (cacheImages && cacheDir != null)
		{
			String imageName = imageUrl.substring(imageUrl.lastIndexOf('/') + 1);
			File file = new File(cacheDir, imageName);
			if (file.exists())
			{
				return BitmapFactory.decodeFile(cacheDir + "/" + imageName);
			}
			else
			{
				Bitmap bitmap = Helpers.getImage(imageUrl, context);
				if (bitmap != null)
					Helpers.saveFile(bitmap, cacheDir + "/" + imageName);
				return bitmap;
			}
		}
		else
		{
			return Helpers.getImage(imageUrl, context);
		}
	}

	// Task for the queue
	private class PhotoToLoad
	{
		public SmallPreview preview;
		public ImageView imageView;

		public PhotoToLoad(SmallPreview preview, ImageView i)
		{
			this.preview = preview;
			imageView = i;
		}
	}

	PhotosQueue photosQueue = new PhotosQueue();

	public void stopThread()
	{
		photoLoaderThread.interrupt();
	}

	// stores list of photos to download
	class PhotosQueue
	{
		private Stack<PhotoToLoad> photosToLoad = new Stack<PhotoToLoad>();

		// removes all instances of this ImageView
		public void clean(ImageView image)
		{
			synchronized (photosToLoad)
			{
				try
				{
					int index = photosToLoad.indexOf(image);
					while (index > -1)
					{
						photosToLoad.remove(index);
						index = photosToLoad.indexOf(image);
					}
				}
				catch (ArrayIndexOutOfBoundsException e)
				{

				}
			}
		}
	}

	class PhotosLoader extends Thread
	{
		public void run()
		{
			try
			{
				while (true)
				{
					// thread waits until there are any images to load in the
					// queue
					if (photosQueue.photosToLoad.size() == 0) synchronized (photosQueue.photosToLoad)
					{
						photosQueue.photosToLoad.wait();
					}
					if (photosQueue.photosToLoad.size() != 0)
					{
						PhotoToLoad photoToLoad;
						synchronized (photosQueue.photosToLoad)
						{
							photoToLoad = photosQueue.photosToLoad.pop();
						}
						Bitmap bmp = getBitmap(photoToLoad.preview.imageUrl);
						if (bmp != null)
							cache.put(photoToLoad.preview, bmp);
						Object tag = photoToLoad.imageView.getTag();
						if (tag != null && ((SmallPreview) tag).equals(photoToLoad.preview))
						{
							BitmapDisplayer bd = new BitmapDisplayer(bmp, photoToLoad.imageView);
							Activity a = (Activity) photoToLoad.imageView.getContext();
							a.runOnUiThread(bd);
						}
					}
					if (Thread.interrupted()) break;
				}
			}
			catch (InterruptedException e)
			{
				// allow thread to exit
			}
		}
	}

	PhotosLoader photoLoaderThread = new PhotosLoader();

	// Used to display bitmap in the UI thread
	class BitmapDisplayer implements Runnable
	{
		Bitmap bitmap;
		ImageView imageView;

		public BitmapDisplayer(Bitmap b, ImageView i)
		{
			bitmap = b;
			imageView = i;
		}

		public void run()
		{
			if (bitmap != null)
				imageView.setImageBitmap(bitmap);
			else
				imageView.setImageResource(stub_id);
		}
	}

	public void clearCache()
	{
		// clear memory cache
		cache.clear();

		// clear SD cache
		File[] files = cacheDir.listFiles();
		for (File f : files)
			f.delete();
	}

}
